JPH04245662A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To easily form fine element isolation with progress in high integration of a semiconductor integrated circuit. CONSTITUTION:A groove is formed in the depth of 0.5mum on a semiconductor silicon substrate 11 with the anisotropic dry etching method using a resist pattern 12 formed by the photolithography technology as a mask (Fig 1(b)). (CH3)4 NOH is added to the saturated aqueous solution 13 obtained by solving silicon dioxide into hydrogen hexafluoro silicate to precipitate silicon dioxide (Fig. 1(c)). The precipitated silicon dioxide is deposited and the silicon oxide film 15 is selectively grown in the groove of substrate at the growth temperature of 40 deg.C until the groove is perfectly filled with the silicon dioxide (Fig. 1(d)). Thereafter, a resist pattern 12 is removed to form element isolation (Fig. 1(e). With this method, uniform fine element isolation can easily be formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device that improves fine element isolation technology for semiconductor devices.

0002

2. Description of the Related Art An integrated circuit includes a plurality of active elements separated from each other by an insulating layer on a common semiconductor silicon substrate. In a conventional method for manufacturing a semiconductor device using element isolation technology, a semiconductor substrate is separated into an active region and a field region via a buried insulator, and elements are formed in the active region. ).

First, a resist pattern 12 is formed on a semiconductor silicon substrate 11 (FIG. 4(a)). Using the resist pattern 12 as a mask, the semiconductor silicon substrate 11 is etched by dry etching to a depth necessary for element isolation (FIG. 4(b)). The resist pattern 12 is removed, and an oxide film 41 is deposited on the semiconductor silicon substrate 11 until the groove in the substrate is completely filled (FIG. 4(c)). A resist 42 is applied on the oxide film 41 for planarization (FIG. 4(d)). Dry etching is performed on the resist 42 and the oxide film 41 under conditions of equal etch rate to expose the surface of the semiconductor silicon substrate and form element isolation (FIG. 4(e)).

[0004] By the method described above, it is possible to perform element isolation using an insulating film of a semiconductor device. but,
In this method, a resist is applied on the oxide film and flattened.
An etch-back process is required, increasing the number of steps. Moreover, if the separation width, that is, the width of the groove in the substrate, is narrow in some places and wide in others, a complicated process is required to achieve complete planarization.

[0005]

[Problems to be Solved by the Invention] As mentioned above, in this conventional manufacturing method, as shown in FIG. 4(d), it is necessary to apply a resist on the oxide film, planarize it, and etch back. , the number of processes increases. Moreover, if the separation width, that is, the width of the groove in the substrate, is narrow in some places and wide in others, a complicated process is required to achieve complete planarization. Also,
It is very difficult to etch back uniformly within the wafer surface, making it difficult to uniformly form element isolation. Therefore, when conventional element isolation techniques are used, the process becomes complicated and uniform element isolation cannot be obtained, which is a major obstacle to lowering the cost and achieving high reliability of semiconductor integrated circuits.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a semiconductor device that achieves fine element isolation.

[0007]

[Means for Solving the Problems] The present invention includes a step of forming a resist pattern on a semiconductor substrate by lithography technology, a step of etching the semiconductor substrate using the resist pattern as a mask to form a groove, and a step of etching the semiconductor substrate using the resist pattern as a mask. A method for manufacturing a semiconductor device, comprising the steps of: selectively growing an insulator in a liquid phase in a trench to fill the trench to form an element isolation region; and removing the resist pattern. This is what we provide. In particular, the liquid phase growth of the insulator is characterized in that silicon dioxide is precipitated by adding an alkaline aqueous solution to a saturated aqueous solution in which silicon dioxide is dissolved in hydrofluorosilicic acid, thereby depositing a silicon oxide film. A method for manufacturing a semiconductor device is provided. Further, the present invention provides the method for manufacturing a semiconductor device described above, wherein the liquid phase growth of the insulator is preferably performed at a temperature of 40° C. or lower.

The present invention also includes a step of forming a resist pattern on a semiconductor substrate by lithography technology;
a step of etching the semiconductor substrate using the resist pattern as a mask to form a groove; a step of selectively growing an insulator in the groove in a vapor phase to fill the groove to form an element isolation region; The present invention provides a method for manufacturing a semiconductor device, comprising the step of removing a resist pattern. In particular, the present invention provides the method for manufacturing the semiconductor device described above, characterized in that the vapor phase growth of the insulator involves depositing a silicon oxide film using vapors of hydrofluorosilicic acid and aqueous alkaline solution. and,
Preferably, the method for manufacturing a semiconductor device described above is characterized in that the vapor phase growth of the insulator is performed at 200° C. or lower.

Furthermore, the present invention includes a step of depositing a silicon oxide film on a semiconductor substrate, a step of forming a resist pattern on the silicon oxide film by lithography technology, and a step of depositing a silicon oxide film on the silicon oxide film using the resist pattern as a mask. a step of etching an oxide film, a step of etching the semiconductor substrate to form a groove, a step of removing the resist pattern, and selectively growing an insulator in the groove in a vapor phase to fill the groove. The present invention provides a method for manufacturing a semiconductor device, comprising a step of forming an element isolation region and a step of removing the silicon oxide film. Further, there is provided the method for manufacturing a semiconductor device as described above, wherein the vapor phase growth of the insulator is preferably performed at 300°C to 500°C.

0010

[Operation] The present invention uses the above-described semiconductor device manufacturing method to form a groove in a semiconductor substrate and selectively deposit an insulator in the groove. The process is no longer necessary. Therefore, the process is simplified and uniform element isolation can be formed. In particular, by performing selective embedding of insulators in the liquid phase, low-temperature formation (below 40°C) is possible, and the resist pattern used as a mask for trench formation on a semiconductor substrate can be used as is as a mask for liquid-phase selective growth. is possible and further simplifies the process. Furthermore, by performing selective embedding of the insulator in the gas phase, the growth rate becomes faster than in the case of the liquid phase. In particular, in vapor phase growth at a low temperature of 200° C. or lower, the resist pattern used as a mask for forming grooves in a semiconductor substrate can be used as is as a mask for vapor phase selective growth, further simplifying the process. Therefore, by using the present invention, the process is simplified and it is effective in forming uniform fine element isolation in a semiconductor device.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a semiconductor device according to an embodiment of the present invention will be described below with reference to the drawings.

(FIG. 1) shows a process cross-sectional view of a method for manufacturing a semiconductor device in an embodiment of the present invention. A resist pattern 12 was formed on a semiconductor silicon substrate 11 by photolithography (FIG. 1(a)). Using the resist pattern 12 as a mask, a groove with a depth of 0.5 μm was formed in the semiconductor silicon substrate 11 by anisotropic dry etching (FIG. 1(b)). Add (CH3)4N to a saturated aqueous solution 13 in which silicon dioxide is dissolved in hydrofluorosilicic acid.
OH was added to precipitate silicon dioxide (Fig. 1(c)
)). The precipitated silicon dioxide was deposited on the substrate and
At a growth temperature of °C, a silicon oxide film 15 was selectively grown in the grooves of the substrate until the grooves were completely filled (FIG. 1(d)).
. In this case, the silicon oxide film grows on the silicon, but not on the resist. Thereafter, the resist pattern 12 was removed to form element isolation (FIG. 1(e)
)).

As described above, according to this embodiment, a groove is provided in the semiconductor substrate and a silicon oxide film is selectively deposited in the groove, so that the planarization and etch-back steps are not required as in conventional element isolation technology. is no longer required, the process is simplified,
Uniform element isolation could be formed. Furthermore, by performing selective embedding of the silicon oxide film in the liquid phase, low-temperature formation is possible, and the resist pattern used as a mask for trench formation on a semiconductor substrate can be used as is as a mask for liquid phase selective growth. , the process was further simplified.

In this embodiment, a silicon oxide film is used for selective liquid phase growth, but other insulating films capable of selective liquid phase growth may be used. Furthermore, although the liquid phase growth temperature was set at 40° C., it may be lower than that.

A second embodiment of the present invention will be described below with reference to the drawings. (FIG. 2) shows a process cross-sectional view of a method for manufacturing a semiconductor device in an embodiment of the present invention. A resist pattern 12 was formed on a semiconductor silicon substrate 11 by photolithography technology (Fig. 2(a)
)). Using the resist pattern 12 as a mask, the semiconductor silicon substrate 11 is etched to a depth of 0 by anisotropic dry etching.
．． A groove of 5 μm was formed (FIG. 2(b)). Steam 21 of hydrofluorosilicic acid and (CH3)4NOH was blown onto the substrate to deposit silicon dioxide (FIG. 2(c)). By the method described above, a silicon oxide film 15 was selectively grown in the groove portion of the substrate at a growth temperature of 200° C. until the groove was completely filled (FIG. 2(d)). In this case, the silicon oxide film grows on the silicon, but not on the resist. Thereafter, the resist pattern 12 was removed to form element isolation (FIG. 2(e)).

As described above, according to this embodiment, a groove is provided in the semiconductor substrate and a silicon oxide film is selectively deposited in the groove, so that the planarization and etch-back steps are not required as in conventional element isolation technology. is no longer required, the process is simplified,
Uniform element isolation could be formed. In addition, by selectively filling the silicon oxide film at low temperatures, the resist pattern used as a mask for trench formation on a semiconductor substrate can be used as a mask for vapor phase selective growth, further simplifying the process. .

In this embodiment, a silicon oxide film was used for selective vapor phase growth, but other insulating films that can be grown selectively in vapor phase at low temperatures may also be used. Further, although the temperature of vapor phase growth was set to 200° C., it may be lower than that.

(FIG. 3) is a cross-sectional view showing a process for manufacturing a semiconductor device according to an embodiment of the present invention. A silicon oxide film 31 with a thickness of 0.1 μm is formed on the semiconductor silicon substrate 11.
A resist pattern 12 was formed on the silicon oxide film 31 by photolithography (FIG. 3(a)).
)). The silicon oxide film 31 was selectively removed by anisotropic dry etching using the resist pattern 12 as a mask, and a groove with a depth of 0.5 μm was formed in the semiconductor silicon substrate 11 (FIG. 3(b)). The resist pattern 12 was removed (FIG. 3(c)). By vapor phase growth using tantalum chloride and ozone gas at 400° C., a tantalum oxide film 32 was selectively grown in the grooves of the substrate until the grooves were completely filled (FIG. 3(d)). In this case, the tantalum oxide film grows on silicon, but not on the silicon oxide film. Thereafter, the silicon oxide film 31 was removed to form element isolation (FIG. 3(e)).

As described above, according to this embodiment, a groove is provided in the semiconductor substrate and a tantalum oxide film is selectively deposited in the groove, so that the planarization and etch-back steps are not required as in conventional element isolation technology. is no longer required, the process is simplified,
Uniform element isolation could be formed.

In this embodiment, a tantalum oxide film was used for selective vapor phase growth, but other insulating films capable of selective vapor phase growth may be used. In addition, the temperature of vapor phase growth was set to 400℃.
However, it is sufficient as long as selective growth is possible.

[0021]

As explained above, according to the method of manufacturing a semiconductor device of the present invention, a groove is provided in a semiconductor substrate and an insulator is selectively deposited in the groove, so that it is different from conventional element isolation technology. planarization and etch-back steps are no longer required. Therefore, the process is simplified and uniform element isolation can be formed. In particular, by performing selective embedding of insulators in the liquid phase, low-temperature formation (below 40°C) is possible, and the resist pattern used as a mask for trench formation on a semiconductor substrate can be used as is as a mask for liquid-phase selective growth. is possible and further simplifies the process. In this case, since element isolation can be formed by a low temperature process, good element isolation without thermal distortion and crystal defects can be achieved. Furthermore, by performing selective embedding of the insulator in the gas phase, the growth rate becomes faster than in the case of the liquid phase. In particular, in vapor phase growth at a low temperature of 200° C. or lower, the resist pattern used as a mask for forming grooves in a semiconductor substrate can be used as is as a mask for vapor phase selective growth, further simplifying the process. Therefore, by using the present invention, the process is simplified,
Since it effectively acts on the formation of uniform fine element isolation, it can greatly contribute to lower costs and higher reliability in the production of ultra-high density integrated circuits.

[Brief explanation of the drawing]

FIG. 1 is a process cross-sectional view of a method for manufacturing a semiconductor device in a first embodiment of the present invention.

FIG. 2 is a process cross-sectional view of a method for manufacturing a semiconductor device according to a second embodiment of the present invention.

FIG. 3 is a process cross-sectional view of a method for manufacturing a semiconductor device according to a third embodiment of the present invention.

FIG. 4 is a process cross-sectional view of a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

11 Semiconductor silicon substrate 12 Resist pattern 13 Hydrofluorosilicic acid saturated aqueous solution 14
Alkaline aqueous solution addition 15 Silicon oxide film 21 Steam 31 Silicon oxide film 32 Tantalum oxide film 41 Oxide film 42 Resist

Claims (8)

[Claims] 1. A step of forming a resist pattern on a semiconductor substrate using a lithography technique, a step of etching the semiconductor substrate using the resist pattern as a mask to form a groove, and selectively applying an insulating material to the groove portion. 1. A method of manufacturing a semiconductor device, comprising the steps of: forming an element isolation region by filling the trench by liquid phase growth; and removing the resist pattern. [Claim 2] Liquid phase growth of an insulator is characterized in that silicon dioxide is precipitated by adding an alkaline aqueous solution to a saturated aqueous solution in which silicon dioxide is dissolved in hydrofluorosilicic acid, and a silicon oxide film is deposited. Claim 1
A method of manufacturing the semiconductor device described above. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the liquid phase growth of the insulator is performed at a temperature of 40° C. or lower. 4. A step of forming a resist pattern on a semiconductor substrate by a lithography technique, a step of etching the semiconductor substrate using the resist pattern as a mask to form a groove, and selectively applying an insulating material to the groove portion. A method for manufacturing a semiconductor device, comprising the steps of forming an element isolation region by vapor phase growth and burying the trench, and removing the resist pattern. 5. The method of manufacturing a semiconductor device according to claim 4, wherein in the vapor phase growth of the insulator, a silicon oxide film is deposited using vapors of hydrofluorosilicic acid and an alkaline aqueous solution. 6. The method of manufacturing a semiconductor device according to claim 4, wherein the vapor phase growth of the insulator is performed at a temperature of 200° C. or lower. 7. A step of depositing a silicon oxide film on a semiconductor substrate, a step of forming a resist pattern on the silicon oxide film by lithography technology, and a step of etching the silicon oxide film using the resist pattern as a mask. a step of etching the semiconductor substrate to form a groove; a step of removing the resist pattern; and selective vapor phase growth of an insulator in the groove to fill the groove to form an element isolation region. 1. A method of manufacturing a semiconductor device, comprising: a step of removing the silicon oxide film. 8. The vapor phase growth of the insulator is carried out at 300°C to 50°C.
8. The method of manufacturing a semiconductor device according to claim 7, wherein the growth is performed at 0°C.